Patent Document 1 discloses a composition for forming a resist underlayer film for lithography, which includes a polymer having a disulfide bond, that is, an “S—S bond” in the main chain, and a solvent, and additionally includes a crosslinkable compound and a sulfonic acid compound.
Patent Document 2 discloses a composition for forming a resist underlayer film which includes (A) a resin, (B) a crosslinking agent having a butyl ether group and (C) a solvent and in which a crosslinking agent having the (B) butyl ether group is a nitrogen-containing cyclic compound having at least two butyl ether groups and the nitrogen-containing cyclic compound is a compound having a glycoluril framework or a triazine framework.
[Patent Document 1] PCT International Publication No. WO 2009/096340
[Patent Document 2] PCT International Publication No. WO 2008/143302